Canadian Anthrax Outbreak Worsens

An anthrax outbreak that began in early July has claimed 637 animals and caused 134 premises to be quarantined in Saskatchewan, Canada, as of Aug. 10, according to the Canadian Food Inspection Agency (CFIA). The outbreak is the largest on record to ever hit Saskatchewan. In Manitoba, Canada, CFIA officials confirmed anthrax cases on 18 premises, with 126 dead animals reported.

According to CFIA veterinarians, more than 250,000 animals have been privately vaccinated and 18,000 vaccinated by the Canadian government. Animals infected by the outbreak include cattle, horses, bison, sheep, and goats.

Anthrax is zoonotic disease--meaning it can be transmitted to humans by an infected animal or animal product--caused by the bacteria Bacillus anthracis or its spores. The spores are highly resistant to harsh weather conditions, so the bacteria can survive in the soil for years. Anthrax naturally occurs in grazing animals (cattle, sheep, and goats), but virtually all mammals, including horses, can contract this disease.

Most of the farms under the 30-day quarantines raise cattle, but other premises housing horse, swine, bison, and white-tailed deer have also been quarantined. Although anthrax is not as common in horses, those that ingest spores usually develop a very high fever and show signs of colic and/or diarrhea. They might also develop difficulty breathing (dyspnea) and can develop swelling on the underside of the neck and chest.

Treatment (fluids, antibiotics, and anti-inflammatory medications) can be successful, but anthrax is usually fatal to horses if not treat early in the course of the disease.

Several U.S. areas have also been dealing with anthrax outbreaks, although they are minor in comparison to Canada's and seem to be slowing down.

"To the best of my knowledge, no new cases of anthrax have been confirmed by the lab since 28 July, 2006," said Randy Lindemann, DVM, North Dakota district veterinarian. "I have a stack of eight submissions to the Veterinary Diagnostic Laboratory, North Dakota State University, all of which are negative. This deal appears to have stopped short. We were having extreme heat with temps in the triple digit range at about that time. I don't know if that plays a role or not. I also don't know what to expect from here on."